Tachometer



Oct. 14, 1947. J. BERGE 2,428,828

TACHOMETER Filed Oct. 20, 1943 INVENTOR. By W 16mm Jma Patented Oct. 14, 1947 TACHOMETER;

Joseph Berge, .Maplewood, N.. J'., assignor. to.

J aeger Watch Conip'an y, 1110.. New York, N. Y.,

a corporation of New York Applicationioctober- 20, 1943,.Serial No. 507,007 (Cl. 235-103.).

2 Claims.

This invention relates -to.in.dicators, and more particularly to, the typeqknown, as tachometers which are employed for-determining the number, of revolutions-per minute of a: drivenshaftzor the like.

One object of the present invention; is to -pro-.

vide a novel tachometer mechanism of strong and compact construction which simplifies manufacture and, in.addition, provides a more rugged mechanism; which isadapted co-withstand hard use withoutloss of. accuracy. r

Anotherobject is to provideanovel tachometer mechanism .zwherein .all 1 the.:-.component parts thereof may-be assembled and adjusted prior to mounting and enclosingsaid. parts within the usual casing.

Another object is to:,provide1 a tachometer meohanismhaving novel-:indicator driving, means whereby said indicatoryisl-rotated always in the. same direction regardless of -thev direction of retation of the shaft engagingspindle of said mechanism.

The above and further objects and novel fea tures of the invention will'morefully, appear from the following detailed description when the same is read in connection -wit-h .-.the; accompanying drawings. Itis to-be expressly. understood; however, that the drawings are for the purpose of illustration only and areinot intended to define the limits of theqinvention, reference for this, latter purpose beingpr-imarily had' tothe appended claims;

In the drawings, wherein like reference characters refer to like. parts throughout theseveral v1ews,

Fig. 1 is a top plan vifiW, n reduced scale; of a tachometer embodyingthe present invention;

Fig. 2 is an enlarged vertical-sectional view of the tachometer illustrated in Fig. 1, with the casing thereof: shown in dottedlines;

Fig. 3 is a horizontal sectional view on the line 3-3 of Fig. 2;

Fig. 4 is a horizontal sectional view. on the line 4-4 of Fig: 2;

Fig. 5 is an enlargedfragmentary sectional view on the line 5- 5 of Fig; 4; and,

Fig. 6 is an enlarged fragmentary sectional view onthe line 6-45 of Fig, 4. .7

The novel tachometer contemplated by the present invention comprises a main base plate or frame member ID, spaced back and. top plates H and I2, respectively, and a dial I3 (Fig; 2),. Back plate H is secured to frame member lllin spaced relation by aplurality of spacers I4 (Fig. 4) having corresponding ends thereofriveted or otherwise suitably secured to plate II. The -opposite ends of; spacers l4 engage the upper surface-of frame member [0 and'are provided with suitable threaded open ingsflto receive screws I5 which project upwardly through suitable openings in said member.v Plate I21is secured to back plate -ll in spacedrelation spacers 5 (Figs. 2 and 3) havingcorresponding ends thereof riveted or otherwise suitably securedto plate II. The opposite-ends of spacers I5 support plate-l2 and are provided with threaded openings to receive screws I! which project downwardly through openings in plate I2. Dial, I3. is secured to top plate l2 in spacedrelation by spacers I8 (Fig. 2) having corresponding ends thereof riveted or otherwise suitablysecured to plate 12. The opposite ends oi spacers 18 support dial 115 and are provided with threaded openings to receive screws I0 (Fig. 1) which project downwardly through suitable, openings in saiddial. Dial l3, as herein shown, is provided with graduations 20 to indicate the number of revolutions per minute in hundreds, and'with other graduations 2| to indicate the number of revolutions per minute in thousands. v

, The base plate or. frame member lfl has secured thereto or formed integrally therewith an upwardly projecting and radially extending boss 22 (Figs. 2 and 4) whichprovides a substantial bearing in which is-journalled the reduced portion 23'of a shaft engaging spindle 24. The outer end of spindle 24 is pointed as indicated at 25 to secure proper engagement of said spindle with a rotating shaft forfrotation thereby to accurately indicatethe speed of said shaft. The innerend of spindle 24 is preferably provided With a hemispherical projection 26 which engages a hardened steel stud 21 supported by: plate [0 to hold said spindle against inward, movement upon engagement of. the latter with a rotatingshaft, thus eliminating drag and frictional contact of the spindle on the outer end of the boss 22, and providing, through point contact of said ball with said stud, a freely rotatablespindle. Asshown, stud.2 1 is carried by an upwardly projecting lug or ear 28 secured to .or formed integrally with frame member If). The bearing 22 and lug 28 on frame member I0 thus provide asubstantial sup,

or said ball may be a separate ball bearing rtatably mounted in a suitable opening in the end of spindle 24, while stud 21 may be a pad or disc formed integrally with lug 28.

Pinned or otherwise suitably secured to the inner end of the reduced portion 23 of spindle 24 for rotation thereby, and disposed between the boss 22 and lug 28, is a worm 29 (Figs. 2 and 4). Frame member [8 and back plate I l are provided with windows 30 and 3|, respectively, to provide sufficient clearance for the worm 29.

Novel means are provided for transmitting the rotation of spindle 24 to speed indicating means hereinafter described, whereby said indicating means are always rotated in the same direction regardless of the direction of rotation of said spindle. In this manner a single set of graduations on dial i3 is only required, thus facilitating reading of the indicated speeds. As herein shown, said transmitting means are preferably constructed, mounted and operated as follows:

Worm 23 meshes with and drives an idler gear 32 (Figs. 4 and 5) journalled on a stud 33 that is threaded and fixed in the frame member 16 by a nut 34, said stud being provided with an enlarged head 35 to prevent displacement of said gear from said frame member. Gear 32 meshes with and drives an idler gear 36 which, in turn, meshes with and drives a similar idler gear 3?. Gears 32, 36 and 31 are continuously in mesh with each other, the gears 36 and 31, however, being adapted to independently and automatically mesh with a large gear 38 through rotation of gear 32 dependent on the direction of rotation of spindle 24. Accordingly gears 36 and 3! are journalled on a swing-arm indicated broadly at 38 (Fig. 4) which, as shown herein, is preferably constituted by a pair of plates or arms 60 and GI (Figs. 5 and 6) that are secured together in spaced relation by spacers 42 and screw 43. Spacers A2 are provided with reduced ends 44 which are engaged in suitable openings in plates 68, 4| to hold said spacers in position, and screw 43 projects downwardly through a suitable opening in plate 40 and is threaded in a suitable threaded opening in plate M to securely clamp said plates together.

Gears 36 and 31 which are mounted between the plates 48 and 4f have secured thereto in any suitable manner, pins 45 which are journalled in suitable bearings in said plates (Fig. 5). Swing-arm 33 is pivotally mounted on the frame member I8 by a stud 46 which extends downwardly through suitable openings in plate 4! and said frame member and is threaded on the lower end thereof to receive a nut 41 for securing said stud to said frame member. Stud 46 is also provided on the upper end thereof with an enlarged head 58 to prevent displacement of swingarm 39 from frame member ID, said head being disposed within a counterbore 43 formed in the plate H to prevent interference of the head with gears 33 and 31.

t will thus appear that when the spindle 24 is rotated in the direction of the arrow R (Fig. 4) gear 32 will be rotated in a counter-clockwise direction, as viewed in Fig. 4, by the worm 29. Under these conditions, swing-arm 39 will first be rocked about the pivot 4-6 in a clockwise direction, as viewed in Fig. 4, through rotation of gear 32 and engagement of the latter with gear 35, thus moving gear 31 into meshing engagement with gear 38, and moving gear 36 out of meshing engagement with gear 38 as indicated in full lines in Fig. 4. Thereupon gear 3'! will be rotated by gear 36 through continued rotation of gear 32, resulting in rotation of gear 33 in a clockwise direction, as viewed in Fig. 4. When the spindle 28 is rotated in the direction of the arrow L (Fig. 4), the above described operations are reversed, that is, gear 32 will then be rotated in a clockwise direction, whereupon swing-arm 33 will be rocked in a counter-clockwise direction to the dotted line position thereof indicated in Fig. 4, resulting in engagement of gear 35 with gear 38, and disengagement of gear 31 from gear 38 as indicated in dotted lines in Fig. 4. Gear 38 will thus be rotated by gear 36 in a clockwise direction.

Rocking movement of swing-arm 33 in opposite directions is limited by stop means to insure proper engagement of gears 35 and 31 with gear 38. Said stop means may be of any suitable construction, but, as herein shown, preferably comprises a pair of eccentric screws 53 (Figs. 4 and 6) which are threaded in suitable threaded openings in the frame member If] and project upwardly on opposite sides of the swing-arm 39 and into the path of movement of the plate 41. The rocking movement of swing-arm 39 in opposite directions may be limited and varied by turning the screws 56, thus obtaining proper meshing engagement of gears 36 and 31 with gear 38.

Gear 38 is loosely mounted on a pointer shaft 51 (Fig. 2) extending vertically of the tachometer mechanism and which is journalled at opposite ends thereof in suitable bearings formed in frame member l6 and top plate l2. Shaft 5i is provided intermediate the ends thereof with an enlarged portion 52 which is engaged by gear 38 to hold the latter against upward movement. Back plate H is formed with an enlarged central opening 33 to provide suincient clearance for shaft 5! and enlarged portion 52 thereof. Shaft 5! is rotated by gear 38 through the medium of a friction spring coupling 54 which is engaged with said shaft and said gear and disposed between the latter and the frame member 0. The upper free end of shaft 5| extends through a suitable opening in the dial l3, and has secured thereto in any suitable manner a hand or pointer 55 for the graduations '20 on said dial.

Journalled in suitable bearings in the back plate I i and top plate I2 is a second pointer shaft 56 (Fig. 2) the upper free end of which extends through a suitable opening in dial [3 and has secured thereto in any suitable manner a pointer or hand 5'! for the graduations 2| on said dial. Shaft 56 is driven from shaft 5! in proper timing to move pointer 51 a single graduation for each complete revolution of pointer 55. For this purpose, shaft 51 has secured thereto in any suitable manner adjacent the underside of plate 12 a gear 58 (Figs. 2 and 3) which meshes with. and drives a larger gear 59. Gear 59 is secured in any suitable manner to a stub shaft 66 (Fig. 3) which is journalled at opposite ends thereof in suitable bearings formed in plates II and i2. Shaft 58 has secured thereto or formed integrally therewith a pinion 6| which meshes with and drives a gear 62 that is secured in any suitable manner to the shaft 56. Shaft 56 will thus be driven through the described driving connections therefor with shaft 51 in the same clockwise direction as shaft 5| to move pointer 51 a single graduation for each complete. revolution of pointer 55. Pointers 55 and 51 are reset in the well known manner after each operation by suitable means (not shown but well known in the art) associated with shafts El and 56 and actuated by a push button 63 (Fig. 1),

The assembled tachometer mechanism unit is enclosed within a case 64 and firmly secured to said case by a plurality of screws 65 which project upwardly through suitably spaced openings in the case and are threaded in suitable threaded openings 86 (Fig. 4) formed in frame member ID, the spindle 24 and a portion of the bearing 22 projecting outwardly through a suitable opening in said case.

There is thus provided a tachometer mechanism of unitary construction wherein all the component parts thereof are carried by a main frame member, thereby enabling assembling and adjusting of said parts as a single unit prior to enclosing and securing said mechanism within a casing, thus eliminating the necessity for two adjustments of said mechanism. Further, the unitary construction of the tachometer mechanism simplifies manufacturing thereof, and at the same time provides a more rigid and compact mechanism which is adapted to withstand hard use without loss of accuracy. The present invention also embodies improved driving means for rotating the pointers of the tachometer in one direction only regardless of the direction of rotation of the shaft contacting spindle, said means making it possible to employ but a single set of graduations which facilitates reading of the indicated speeds.

Although only a single embodiment of the invention has been illustrated and described in the foregoing specification, it is to be expressly understood that changes may be made therein, particularly in the design and arrangement of the parts illustrated, without departing from the spirit and scope of the invention, as will now be clear to those skilled in the art. For a definition of the limits of the invention, reference will be had primarily to the appended claims.

What is claimed is:

1. In a tachometer mechanism of the type having a spindle rotatable in opposite directions, a worm on said spindle, a pointer shaft adapted to be rotated by said spindle, and a gear on said pointer shaft, the combination of means for rotating said pointer shaft in one direction only regardless of the direction of rotation of said spindle, comprising an idler gear engaged with said worm, a swing-arm, a first gear journalled on said swing-arm and engaged with said idler gear, and a second gear journalled on said swingarm and engaged with said first gear, said swingarm being rocked in opposite directions through rotation of said idler gear to move one or the other of said first and second gears into engagement with the pointer shaft gear dependent on the direction of rotation of said spindle, and adjustable eccentric means for limiting the rocking movement of said swing-arm in opposite directions.

2. In a tachometer mechanism of the type having a frame member, a bearing on said frame member and extending radially thereof, a spindle journalled in said bearing and rotatable in opposite directions, a worm on said spindle, a, top plate supported by said frame member in spaced relation therewith, a pointer shaft journalled in said frame member and said plate and adapted to be rotated by said spindle, and a gear on said pointer shaft, the combination of means for rotating said pointer shaft in one direction only regardless of the direction of rotation of said spindle, comprising an idler gear journalled on said frame member and engaged with said Worm, a swing-arm pivotally mounted on said frame member, a first gear journalled on said swing-arm and engaged with said idler gear, and a second gear journalled on said swing-arm and engaged with said first gear, said swing-arm being rocked in opposite directions through rotation of said idler gear to move one or the other of said first and second gears into engagement with the pointer shaft gear dependent on the direction of rotation of said spindle, and adjustable screw threaded eccentric means carried by said frame member and disposed on opposite sides of said swing-arm for limiting the rocking movement of the latter in opposite directions.

JOSEPH BERGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 940,638 Hintze Nov. 16, 1909 1,178,078 Kocourek Apr, 4, 1916 1,490,796 Blomberg Apr. 15, 1924 321,365 Hutches, Jr June 30, 1885 580,432 Starrett Apr. 13, 1897 650,465 Hubbell May 29, 1900 1,297,793 Carson Mar. 18, 1919 1,978,605 Showwalter et a1. Oct. 30, 1934 1,736,064 Walker Nov. 19, 1929 1,447,426 Prouty et al Mar. 6, 1923 

